“…Model-based methods (e.g., [17,23,9]) use a structural model to measure time-varying gait parameters, e.g., gait period, stance width and stride length, and a motion model to analyse the kinematical and dynamical motion parameters of the subject, e.g., rotation patterns of hip and thigh, and joint angle trajectories, to obtain gait signatures. The modelfree gait recognition methods in [4,3,27] analyse the dynamic and/or static gait characteristics of silhouettes or the extreme outer boundary of silhouettes, i.e., contours of a gait sequence. The performance of these methods largely depends on the correctness of the background segmentation techniques, presence of occluding objects in the scene and shadows under feet, as these factors considerably determine the quality of the silhouettes and the extracted contours.…”